[jdk17u-dev] RFR: JDK-8298726: Backport 5f63f7a (fs) Change PollingWatchService to record last modified time as FileTime rather than milliseconds

[Stewart X Addison]

This is a clean backport of https://github.com/openjdk/jdk/pull/11665 which fixes a compliance issue on AIX.
Relevant issue: https://bugs.openjdk.org/browse/JDK-8298726

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Commit messages:
 - Backport 5f63f7a

Changes: https://git.openjdk.org/jdk17u-dev/pull/957/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=957&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8298726
  Stats: 15 lines in 1 file changed: 2 ins; 4 del; 9 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/957.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev pull/957/head:pull/957

PR: https://git.openjdk.org/jdk17u-dev/pull/957